Update WildcardFileFinder.cs

Author: SimonCropp

src/DiffEngine/WildcardFileFinder.cs

@@ -13,7 +13,7 @@ static IEnumerable<string> EnumerateDirectories(string directory)
         {
             if (Directory.Exists(directory))
             {
-                return new List<string> {directory};
+                return [directory];
             }
         }